	function goTop(acceleration, time) {
		acceleration = acceleration || 0.1;
		time = time || 16;
	 
		var x1 = 0;
		var y1 = 0;
		var x2 = 0;
		var y2 = 0;
		var x3 = 0;
		var y3 = 0;
	 
		if (document.documentElement) {
			x1 = document.documentElement.scrollLeft || 0;
			y1 = document.documentElement.scrollTop || 0;
		}
		if (document.body) {
			x2 = document.body.scrollLeft || 0;
			y2 = document.body.scrollTop || 0;
		}
		var x3 = window.scrollX || 0;
		var y3 = window.scrollY || 0;
	 
		// 滚动条到页面顶部的水平距离
		var x = Math.max(x1, Math.max(x2, x3));
		// 滚动条到页面顶部的垂直距离
		var y = Math.max(y1, Math.max(y2, y3));
	 
		// 滚动距离 = 目前距离 / 速度, 因为距离原来越小, 速度是大于 1 的数, 所以滚动距离会越来越小
		var speed = 1 + acceleration;
		window.scrollTo(Math.floor(x / speed), Math.floor(y / speed));
	 
		// 如果距离不为零, 继续调用迭代本函数
		if(x > 0 || y > 0) {
			var invokeFunction = "goTop(" + acceleration + ", " + time + ")";
			window.setTimeout(invokeFunction, time);
		}
	}